US4601574A - Distance measuring apparatus - Google Patents

Distance measuring apparatus Download PDF

Info

Publication number
US4601574A
US4601574A US06/717,604 US71760485A US4601574A US 4601574 A US4601574 A US 4601574A US 71760485 A US71760485 A US 71760485A US 4601574 A US4601574 A US 4601574A
Authority
US
United States
Prior art keywords
distance
subject
receiving
current
energy beam
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US06/717,604
Other languages
English (en)
Inventor
Satoshi Yamane
Toshitatsu Suzuki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ricoh Co Ltd
Original Assignee
Ricoh Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP6674381A external-priority patent/JPS57182112A/ja
Priority claimed from JP6999581A external-priority patent/JPS57192815A/ja
Application filed by Ricoh Co Ltd filed Critical Ricoh Co Ltd
Assigned to RICOH COMPANY, LTD. reassignment RICOH COMPANY, LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SUZUKI, TOSHITATSU, YAMANE, SATOSHI
Application granted granted Critical
Publication of US4601574A publication Critical patent/US4601574A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C3/00—Measuring distances in line of sight; Optical rangefinders
    • G01C3/10—Measuring distances in line of sight; Optical rangefinders using a parallactic triangle with variable angles and a base of fixed length in the observation station, e.g. in the instrument

Definitions

  • This invention relates to a distance measuring apparatus for measuring a distance from its position to a subject of interest and in particular to such a distance measuring apparatus as a range finder for use in a camera and the like.
  • a passive type dual image coincidence system utilizing external light.
  • a passive type dual image coincidence system in which the distance from its position to a subject of interest is determined when the coincidence in position of two images is obtained, it is required to use a movable mirror for varying the position of one image with respect to the other image.
  • the use of such a movable mirror has been a cause of poor durability of prior art distance measuring apparatus.
  • the dual image coincidence system is strongly dependent upon the condition of a subject of interest since it carries out the measurement of distance on the basis of the contrast information of a subject of interest such as a subject to be photographed.
  • prior art apparatus have been disadvantageous in low capability of measuring distance for the case in which a subject of interest has a low contrast or for the case in which a subject of interest is in a dark place.
  • prior art system having a movable part has tended to be complicated in structure, requiring time-consuming adjustments.
  • FIG. 1 there has been proposed an improved active type triangulation distance measuring system having no movable parts, as shown in FIG. 1.
  • a light-emitting section 1 which emits light such as infrared light, which is then reflected by a subject of interest 2, e.g., 2a, 2b, 2c and 2d.
  • the reflected light then impinges upon a light-receiving section 3 including a plurality of photocells, four cells 3a, 3b, 3c and 3d in the embodiment shown.
  • the distance to the subject 2 may be obtained by determining which of the light-receiving elements has received the reflected light.
  • the disadvantages of poor durability and complicated adjustments are obviated.
  • it suffers from a disadvantage of limited resolution in distance measurement because of the quantized structure of the light-receiving section 3.
  • the light receiving section 3 is comprised of four light-receiving elements 3a-3d, as shown in FIG. 1, even if the boundary between two adjacent elements is included, the maximum number of levels results in seven and this number may be further reduced when error is taken into account.
  • Another form of the active type distance measuring system has been the one using ultrasonic waves.
  • an ultrasonic wave is radiated toward a subject of interest and the reflected wave from the subject is received by the system, thereby the distance between the system and the subject is determined by the time expended for going and returning trip.
  • measurement is carried out by a pure electrical processing, which is rather simple; however, a relatively large power supply is required to obtain a high power ultrasonic radiation.
  • a power supply incorporated in a compact-sized camera would be insufficient in generating an effective ultrasonic radiation.
  • a distance measuring apparatus for measuring a distance from a reference point to a subject of interest comprising: means for radiating an energy beam toward the subject of interest; receiving means for receiving the energy beam reflected from the subject, said receiving means including a receiving surface defined between two extreme points and supplying a pair of current signals when the reflected evergy beam impinges upon said receiving surface whereby the ratio of said pair of current signals continuously vary depending upon the location of impingement of the reflected energy beam with respect to the two extreme points; and processing means connected to receive the pair of current signals from the receiving means, said processing means processing the pair of current signals to obtain a distance signal indicating the distance between the reference point and the subject of interest.
  • a distance measuring apparatus for measuring a distance from a reference point to a subject of interest comprising: means for radiating an energy beam toward the subject of interest; receiving means for receiving the energy beam reflected from the subject, said receiving means including a receiving surface defined between two extreme points and supplying first and second current signals the magnitude of each of which is determined by the location of impingement of said reflected energy beam within and with respect to the two extreme points; first extracting means to which the first current signal is supplied to extract a first fluctuating component from said first current signal thereby eliminating the effect of background light; second extracting means to which the second current signal is supplied to extract a second fluctuating component from the second current signal thereby eliminating the effect of background light; and a differential processing means to which the first and second fluctuating components are supplied to obtain a distance signal by taking a difference between the first and second fluctuating components.
  • Another object of the present invention is to provide a distance measuring apparatus which may be easily incorporated into a camera as a rangefinder.
  • a further object of the present invention is to provide an active-type distance measuring apparatus which is not influenced by the surrounding condition.
  • a still further object of the present invention is to provide a distance measuring apparatus having a broad range of distance measurement.
  • a still further object of the present invention is to provide a distance measuring apparatus which is stable in operation and thus accurate in measurement.
  • FIG. 1 is a schematic illustration showing the principle of the prior art active type distance measuring apparatus
  • FIG. 2a is a schematic illustration showing one embodiment of the present invention.
  • FIG. 2b is a schematic illustration showing another embodiment of the present invention.
  • FIGS. 3(a) through (c) are schematic illustrations showing several cases where the beam spot is located at different positions on the position detector 5 used in the apparatus shown in FIG. 2a or 2b;
  • FIG. 4 is a graph showing the characteristics of the position detector 5 with the abscissa indicating the distance to a target subject and the ordinate indicating the current ratio obtained from the position detector;
  • FIG. 5 is a circuit diagram showing a pair of logarithmic converting circuits LA1 and LA2 which are associated with the position detector 5;
  • FIG. 6 is a circuit diagram showing a fluctuating current producing circuit which is connected to the logarithmic converting circuit LA1;
  • FIG. 7 is a circuit diagram showing one example of further processing the output obtained from the circuit of FIG. 6;
  • FIG. 8 is a circuit diagram showing another embodiment of the present invention in which the MOSFET TrM is used.
  • FIG. 9 is a partial circuit diagram showing a further embodiment of the present invention in which a series-connected diode train is used.
  • FIG. 10 is a graph showing the typical characteristics of the transistor Tr4 with the abscissa taken for collector-emitter voltage V CE and the ordinate taken for collector current I C ;
  • FIG. 11 is a circuit diagram showing a still further embodiment of the present invention.
  • FIG. 12 is a waveform diagram which is useful in understanding the operation of the circuit of FIG. 11;
  • FIG. 13 is a circuit diagram for processing signals supplied from a pair of circuits shown in FIG. 11;
  • FIGS. 14 through 17 are circuit diagrams showing several modifications of the present invention.
  • the present distance measuring apparatus comprises a light pulse generator 4, which is preferably structured to radiate a pulse of infrared light because of its invisibility to human eyes as well as sensitivity to a position sensitive detector 5 which will be described in detail later.
  • Light pulse radiated from the light pulse generator 4 is projected to a subject of interest 7 such as 7a, 7b and 7c, the distance to which is to be measured, through a projection lens 6.
  • the reflected light pulse from the subject 7 passes through a light receiving lens 8 and impinges upon the detector 5, forming thereon an image.
  • the detector 5 is a planar-type PIN photodiode manufactured by the use of ion implantation technology and it has a one-dimensional, continuous resolution in position. There is also such a detector of two-dimensional type, which may be used in the present invention as well.
  • a light spot is formed at position 5a when the light is reflected by the subject 7 at position 7a, similarly at position 5b for the subject 7 at position 7b, . . . , and at 5d for the subject 7 at infinity.
  • the relation between the current ratio I L1 /I L2 and the distance T is graphically shown in FIG. 4.
  • a detecting circuit 9 is provided to detect a signal current produced only by a reflected light pulse with eliminating the influence of background light, and such a signal current is supplied to an output circuit 10.
  • FIG. 2a a detecting circuit 9 is provided to detect a signal current produced only by a reflected light pulse with eliminating the influence of background light, and such a signal current is supplied to an output circuit 10.
  • first detecting circuit 9a for receiving one current output from the detector 5
  • second detecting circuit 9b for receiving the other current output from the detector 5.
  • FIG. 5 shows the structure in circuit diagram of a detecting head section including the position sensitive detector 5 and the first and second detecting circuits 9a and 9b.
  • the detector 5 is shown as an equivalent circuit which includes a surface resistor 5 - 1, a parallel resistor 5 - 2, a junction capacitor 5 - 3, an ideal diode 5 - 4, and a current source 5 - 5.
  • a pair of signal currents I L1 and I L2 produced by impingement of a light spot on the detector 5 is supplied to a logarithmic conversion section LA1 comprised of a logarithmic conversion transistor Tr1 and an operational amplifier OA1 and a logarithmic conversion section LA2 comprised of a logarithmic conversion transistor Tr2 and an operational amplifier OA2, respectively.
  • FIG. 6 shows the structure of the detecting circuit including a circuit for eliminating the influence of background light from the logarithmic-converted outputs V L1 and V L2 in accordance with one embodiment of the present invention.
  • the detecting circuit of FIG. 6 should be provided not only for the first signal current I L1 but also for the second signal current I L2 ; however, here is only shown the first detecting circuit 9a for the signal current I L1 .
  • the second signal circuit 9b of the identical structure must be provided for the second signal current I L2 in practical use.
  • the background light current I L1r flows through a transistor Tr1, and the same current passes through a transistor Tr3 through a transistor Tr4.
  • FIG. 7 shows the structure in circuit diagram of the detecting circuit 9 which comprises a pair of operational amplifiers OA5 and OA6 each as a voltage follower and another operational amplifier OA7 as a differential amplifier.
  • the output potentials Va1 and Va2 are supplied to the respective inputs of the amplifier OA7 through the respective amplifiers OA5 and OA6, and the amplifier OA7 supplies as its output a voltage corresponding to the ratio of fluctuating components of the signal currents as indicated in the above equation (7).
  • the output voltage thus obtained is supplied to the output circuit 10 and the sample and hold circuit SH, forming a part of the circuit 10, samples and holds the output voltage thus supplied.
  • the sample and hold circuit SH includes a switch SW2, a capacitor C2 and an operational amplifier OA8 as a voltage follower.
  • the output circuit 10 also includes a plurality of comparators CP, each having its inverting input connected to an individual voltage V1-Vn (V1>V2> . . . >Vn) corresponding to different distances, respectively.
  • the output from the sample and hold circuit SH is commonly supplied to the non-inverting inputs of the comparators CP.
  • the number of the comparators CP corresponds to the number of incremental steps of a distance to be outputted.
  • each of the comparators CP having its inverting input connected from the voltages V2-Vn is connected to one input of a corresponding exclusive--OR circuit EO and also, excepting the downmost comparator EO, to one input of the adjacent, in the downward direction in FIG. 7, exclusive--OR circuit EO, thereby these exclusive--OR circuits EO supply output voltages V 2 '-V n ', respectively.
  • the comparator CP which compares the output voltage from the sample and hold circuit SH with the reference voltage V1, supplies an output voltage V 1 '.
  • the comparator CP which compares the output voltage from the sample and hold circuit SH with the reference voltage Vn, supplies an output voltage V n+1 ' through an inverter IV.
  • the output voltage V 1 ' indicates that the voltage from the sample and hold circuit SH is higher than the reference voltage V1; whereas, the output voltage V n+1 ' indicates that the voltage from the sample and hold circuit SH is lower than the reference voltage Vn.
  • the voltage V 1 ' corresponds to a subject of interest at infinity and the voltage V n+1 ' corresponds to a subject of interest at the closest distance.
  • one of the output voltages V 1 ' through V n+1 ' is always at a high level, and the voltage at a high level constitutes an output signal indicating the distance to the subject 7 which reflected the light pulse.
  • Such an output signal may be used to form a visual indication of the distance or to drive a mechanism for moving the objective of a camera.
  • FIG. 8 shows a modification of the present invention in which use is made of a high input impedance element, e.g., MOSFET TrM in FIG. 8, instead of the voltage follower comprised of the operational amplifier OA4 in FIG. 6.
  • a high input impedance element e.g., MOSFET TrM in FIG. 8
  • the transistor Tr3 in FIG. 6 may be so structured to have a larger emitter area, alternatively, as shown in FIG. 8, the base potential of the transistor Tr3 may be made higher than that of the transistor Tr1 by using a combination of a variable resistor VR and a positive power source +V.
  • FIG. 9 shows a still further modification of the present invention in which the difference (Va1-Va2) is increased by using a series-connected diode train Dn in place of the single diode D1 in FIG. 6. It should also be noted that the output from the detecting circuit 9 may be directly used in some applications.
  • a distance measurement may be carried out simply by detecting fluctuating components of the signal currents produced by a light pulse impinging upon the detector 5.
  • FIG. 11 shows the structure of the first or second detecting circuit designed to obviate the above-described problem associated with the use of a PNP transistor in accordance with one embodiment of the present invention.
  • the first and second detecting circuits 9a and 9b are of an identical structure, only the first detecting circuit 9a will be described here.
  • the current corresponding to signal current I L1 passes through a MOSFET FT1 from a power supply +V CC and it is expanded by an expanding transistor Tr3.
  • the base potential of the transistor Tr3 is set approximately 60 mV higher than the base potential of the transistor Tr1, the current will be expanded by 10 times; on the other hand, if the emitter area of the transistor Tr3 is set twice as large as that of the transistor Tr1, a twice-expanded current will be obtained.
  • the following description is the case where no expansion, or unit expansion, takes place.
  • FIG. 12 graphically represents how the output V O supplied from the operational amplifier OA9 varies in the above-described condition.
  • tp indicates a period of light pulse radiation.
  • the second detecting circuit 9b identical in structure to the above-described first detecting circuit 9a, and an output V O2 similar to V O1 is supplied therefrom.
  • the current ratio corresponding to a distance to be measured is given in the form of voltage signal V DO .
  • the voltage signal V DO may be sampled and held during the on condition of a light pulse by means of a sample and hold circuit SH comprised of a sampling switch SW4, a holding capacitor C3 and an operational amplifier OA11 forming a voltage follower as a buffer.
  • a sample and hold circuit SH comprised of a sampling switch SW4, a holding capacitor C3 and an operational amplifier OA11 forming a voltage follower as a buffer.
  • a sample and hold circuit SH comprised of a sampling switch SW4, a holding capacitor C3 and an operational amplifier OA11 forming a voltage follower as a buffer.
  • a light emitting diode and the like since light emitting efficiency significantly decreases due to temperature increase at the junction, sampling had better be carried out immediately after the establishment of on-condition of a light pulse.
  • Such a scheme of immediate sampling is also advantageous in the case where a cyclic or pulsating component of the
  • the sampled output is comprised of a voltage with its level proportional to a distance, it may be directly used as a distance signal to be applied to an automatic focussing mechanism or to a visual indicator. Alternatively, the sampled output may be further converted into one of a plurality of predetermined signals representing different distance zones with the use of a plurality of comparators and reference voltages.
  • the influence of background light may be eliminated effectively as well as stably thereby allowing to carry out a distance measurement with a high accuracy.
  • the first and second detecting circuits are comprised of such elements as MOSFET, bipolar transistor, operational amplifier, diode, etc., which are all suited in fabricating the circuits in the form of an I.C., and no elements such as junction-type FET's which are not suited for I.C. fabrication are used.
  • FIG. 14 shows the case in which use is made of a combination including an operational amplifier OA12 formed as a voltage follower and an NPN transistor Tr6 instead of the NMOSFET FT1 in FIG. 11.
  • FIG. 15 shows a further modification in which use is made of a Darlington pair comprised of NPN transistors Tr7 and Tr8 in place of the NMOSFET FT1 in the circuit of FIG. 11.
  • This structure has the same advantages as those of the circuit shown in FIG. 14.
  • FIG. 16 shows a still further modification in which use is made of a pair of interconnected operational amplifiers OA13 and OA14 in place of the operational amplifier OA9 in the circuit of FIG. 11.
  • the switch SW2 is kept closed, and input voltage V x to the non-inverting input of the operational amplifier OA13 is set lower in level than input voltage V ref to the non-inverting input of the operational amplifier OA14, thereby maintaining output voltage V O ' to be "L", or low level.
  • no current passes through the logarithmic compression diode D3, and current flows to the transistor Tr3 through the NMOSFET FT1.
  • the switch SW2 may be substituted by a high-valued resistor since it may be omitted by making the time constant of the system larger.
  • an offset voltage of the operational amplifier OA9 will appear in its output if the diode D2 is directly used. That is, denoting the offset amount with V of and the voltage drop of the diode D2 with V D , the following equation may be obtained.
  • FIG. 17 shows another modification of the present invention in which PNP transistor Tr9 is provided in place of the diode D2 in the circuit of FIG. 11.
  • V BE is the base-emitter voltage of the transistor Tr9.
  • the switch SW5 is closed only during light pulse radiation. This is because, if the base of the transistor Tr9 is always connected to ground, current will flow between the collector and base of the transistor Tr9 in a steady state condition, which will increase the level of power consumption.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Measurement Of Optical Distance (AREA)
  • Focusing (AREA)
US06/717,604 1981-05-01 1985-04-01 Distance measuring apparatus Expired - Lifetime US4601574A (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP56-66743 1981-05-01
JP6674381A JPS57182112A (en) 1981-05-01 1981-05-01 Range detector
JP56-69995 1981-05-09
JP6999581A JPS57192815A (en) 1981-05-09 1981-05-09 Distance detecting device

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US06372817 Continuation 1982-04-28

Publications (1)

Publication Number Publication Date
US4601574A true US4601574A (en) 1986-07-22

Family

ID=26407945

Family Applications (1)

Application Number Title Priority Date Filing Date
US06/717,604 Expired - Lifetime US4601574A (en) 1981-05-01 1985-04-01 Distance measuring apparatus

Country Status (2)

Country Link
US (1) US4601574A (enrdf_load_stackoverflow)
DE (1) DE3216246A1 (enrdf_load_stackoverflow)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4721384A (en) * 1985-01-26 1988-01-26 Deutsche Forschungs- Und Versuchsanstalt Fur Luft- Und Raumfahrt E.V. Optical-electronic rangefinder
US4761072A (en) * 1986-09-30 1988-08-02 Diffracto Ltd. Electro-optical sensors for manual control
US4796998A (en) * 1985-10-03 1989-01-10 Pasco Corporation Method for mobile survey of road surface
US4864147A (en) * 1987-06-30 1989-09-05 Matsushita Electric Works, Ltd. Optically scanning displacement sensor with linearity correction means
US4952911A (en) * 1988-05-18 1990-08-28 Eastman Kodak Company Scanning intrusion detection device
US4967183A (en) * 1988-05-18 1990-10-30 Eastman Kodak Company Method of intrusion detection over a wide area
US5005970A (en) * 1988-03-04 1991-04-09 Olympus Optical Co., Ltd. Distance detecting apparatus
US5068540A (en) * 1989-08-04 1991-11-26 Ricoh Company, Ltd. Distance measuring apparatus having automatic gain control
US5107449A (en) * 1988-02-27 1992-04-21 Canon Kabushiki Kaisha Distance measuring device
US5128529A (en) * 1988-12-29 1992-07-07 Seikosha Co., Ltd. Autofocusing device with improved distance focusing accuracy
US5187361A (en) * 1989-04-25 1993-02-16 Copal Company Limited Object detection apparatus of the photoelectric reflection type with sampled data
US5200602A (en) * 1991-07-13 1993-04-06 Ricoh Company, Ltd. Distance measuring device of camera
US5229806A (en) * 1991-05-28 1993-07-20 Chinon Kabushiki Kaisha Multi-point range finding device
US5471046A (en) * 1994-02-25 1995-11-28 Eastman Kodak Company Camera auto-focusing system with designator using a volume holographic element
US5978015A (en) * 1994-10-13 1999-11-02 Minolta Co., Ltd. Stereoscopic system with convergence and dioptric power adjustments according to object distance
US6492652B2 (en) * 1999-12-24 2002-12-10 Hera Rotterdam B.V. Opto-electronic distance sensor and method for the opto-electronic distance measurement
WO2009002327A1 (en) * 2007-06-28 2008-12-31 Thomson Licensing Optical rangefinder for a 3-d imaging system
US20110110595A1 (en) * 2009-11-11 2011-05-12 Samsung Electronics Co., Ltd. Image correction apparatus and method for eliminating lighting component

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59151013A (ja) * 1983-02-18 1984-08-29 Ricoh Co Ltd 距離検出装置
JPS59160108A (ja) * 1983-03-02 1984-09-10 Canon Inc 光半導体位置検出素子の信号処理回路
JPS6465460A (en) * 1987-09-07 1989-03-10 Hitachi Ltd Space filter type speed measuring instrument
DE4115785C2 (de) * 1991-05-15 1994-04-28 Pepperl & Fuchs Verfahren zur optischen Distanzvermessung eines Objektes nach dem Triangulationsprinzip sowie nach diesem Verfahren arbeitende Vorrichtung
RU2178186C1 (ru) * 2000-06-19 2002-01-10 Пицык Виктор Васильевич Способ определения расстояния между точками отражающей поверхности

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3443502A (en) * 1966-08-23 1969-05-13 Eastman Kodak Co Automatic focusing for cameras
US3936187A (en) * 1972-07-19 1976-02-03 Konishiroku Photo Industry Co., Ltd. Distance measuring device
US3951550A (en) * 1974-08-12 1976-04-20 The Magnavox Company Direction-sensing virtual aperture radiation detector
US4040738A (en) * 1975-03-20 1977-08-09 Gulton Industries, Inc. Railroad track profile spacing and alignment apparatus
US4274735A (en) * 1978-05-25 1981-06-23 Canon Kabushiki Kaisha Distance measuring device
US4345827A (en) * 1979-09-27 1982-08-24 Agfa-Gevaert Aktiengesellschaft Distance-measuring system with in-range signalling for use with cameras, alarms, and the like
US4391513A (en) * 1979-12-25 1983-07-05 Canon Kabushiki Kaisha Range finding optical mechanism
US4445029A (en) * 1980-06-16 1984-04-24 Seiko Koki Kabushiki Kaisha Distance detector using a photopotentiometer and a continuous detecting system

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3612890A (en) * 1969-10-13 1971-10-12 Trw Inc Radiation sensitive optical gaging system
US4309603A (en) * 1979-10-17 1982-01-05 Honeywell Inc. Auto focus system

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3443502A (en) * 1966-08-23 1969-05-13 Eastman Kodak Co Automatic focusing for cameras
US3936187A (en) * 1972-07-19 1976-02-03 Konishiroku Photo Industry Co., Ltd. Distance measuring device
US3951550A (en) * 1974-08-12 1976-04-20 The Magnavox Company Direction-sensing virtual aperture radiation detector
US4040738A (en) * 1975-03-20 1977-08-09 Gulton Industries, Inc. Railroad track profile spacing and alignment apparatus
US4274735A (en) * 1978-05-25 1981-06-23 Canon Kabushiki Kaisha Distance measuring device
US4345827A (en) * 1979-09-27 1982-08-24 Agfa-Gevaert Aktiengesellschaft Distance-measuring system with in-range signalling for use with cameras, alarms, and the like
US4391513A (en) * 1979-12-25 1983-07-05 Canon Kabushiki Kaisha Range finding optical mechanism
US4445029A (en) * 1980-06-16 1984-04-24 Seiko Koki Kabushiki Kaisha Distance detector using a photopotentiometer and a continuous detecting system

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4721384A (en) * 1985-01-26 1988-01-26 Deutsche Forschungs- Und Versuchsanstalt Fur Luft- Und Raumfahrt E.V. Optical-electronic rangefinder
US4796998A (en) * 1985-10-03 1989-01-10 Pasco Corporation Method for mobile survey of road surface
US4761072A (en) * 1986-09-30 1988-08-02 Diffracto Ltd. Electro-optical sensors for manual control
US4864147A (en) * 1987-06-30 1989-09-05 Matsushita Electric Works, Ltd. Optically scanning displacement sensor with linearity correction means
US5107449A (en) * 1988-02-27 1992-04-21 Canon Kabushiki Kaisha Distance measuring device
US5005970A (en) * 1988-03-04 1991-04-09 Olympus Optical Co., Ltd. Distance detecting apparatus
US4952911A (en) * 1988-05-18 1990-08-28 Eastman Kodak Company Scanning intrusion detection device
US4967183A (en) * 1988-05-18 1990-10-30 Eastman Kodak Company Method of intrusion detection over a wide area
US5128529A (en) * 1988-12-29 1992-07-07 Seikosha Co., Ltd. Autofocusing device with improved distance focusing accuracy
US5187361A (en) * 1989-04-25 1993-02-16 Copal Company Limited Object detection apparatus of the photoelectric reflection type with sampled data
US5068540A (en) * 1989-08-04 1991-11-26 Ricoh Company, Ltd. Distance measuring apparatus having automatic gain control
US5229806A (en) * 1991-05-28 1993-07-20 Chinon Kabushiki Kaisha Multi-point range finding device
US5200602A (en) * 1991-07-13 1993-04-06 Ricoh Company, Ltd. Distance measuring device of camera
US5471046A (en) * 1994-02-25 1995-11-28 Eastman Kodak Company Camera auto-focusing system with designator using a volume holographic element
US5978015A (en) * 1994-10-13 1999-11-02 Minolta Co., Ltd. Stereoscopic system with convergence and dioptric power adjustments according to object distance
US6492652B2 (en) * 1999-12-24 2002-12-10 Hera Rotterdam B.V. Opto-electronic distance sensor and method for the opto-electronic distance measurement
WO2009002327A1 (en) * 2007-06-28 2008-12-31 Thomson Licensing Optical rangefinder for a 3-d imaging system
US20110110595A1 (en) * 2009-11-11 2011-05-12 Samsung Electronics Co., Ltd. Image correction apparatus and method for eliminating lighting component
US8538191B2 (en) * 2009-11-11 2013-09-17 Samsung Electronics Co., Ltd. Image correction apparatus and method for eliminating lighting component

Also Published As

Publication number Publication date
DE3216246C2 (enrdf_load_stackoverflow) 1991-06-27
DE3216246A1 (de) 1982-12-02

Similar Documents

Publication Publication Date Title
US4601574A (en) Distance measuring apparatus
US5200602A (en) Distance measuring device of camera
US4527892A (en) Distance measuring apparatus
US4681432A (en) Photo-electric converting device
US4682872A (en) Signal processing apparatus for a semiconductor position sensing device
US4644149A (en) Photoelectric transducer element
US5448054A (en) Circuit for use in determining the position of light incident on a position sensing detector
JPS631918A (ja) 距離検出装置
JPH0457962B2 (enrdf_load_stackoverflow)
JPS6233522B2 (enrdf_load_stackoverflow)
JPS6234082B2 (enrdf_load_stackoverflow)
US5309072A (en) Distance measurement apparatus for camera, and distance measurement method
JPS58151511A (ja) 距離検出装置
JPH0326408Y2 (enrdf_load_stackoverflow)
Oike et al. High-performance photo detector for correlative feeble lighting using pixel-parallel sensing
JPS6230363B2 (enrdf_load_stackoverflow)
JPS59151013A (ja) 距離検出装置
Oike et al. High performance photodetector for modulated lighting-high sensitivity, high selectivity, high suppression of background, and wide dynamic range
JP2942593B2 (ja) 被写体距離検出装置
JPH04208909A (ja) 距離検出装置
JP3130559B2 (ja) アクティブ式測距装置
JPH04204011A (ja) 距離検出装置
JPH0618259A (ja) カメラの測距装置
JPH0212008A (ja) 非接触変位測定装置
JPH0160803B2 (enrdf_load_stackoverflow)

Legal Events

Date Code Title Description
AS Assignment

Owner name: RICOH COMPANY, LTD., 3-6, NAKAMAGOME 1-CHOME, OHTA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:YAMANE, SATOSHI;SUZUKI, TOSHITATSU;REEL/FRAME:004522/0630

Effective date: 19820413

STCF Information on status: patent grant

Free format text: PATENTED CASE

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12